Cream
Cream is the name of one of the better known dilutions, responsible for popular colours like palomino and buckskin. It works with the base colours to create palomino and cremello on chestnut, smoky black and smoky cream on black and buckskin and perlino on bay. This dilution is an allele of the MATP gene on horse chromosome 21. Another allele of the same gene is pearl, a rare dilution that's very old, but only recently discovered. The two dilutions can combine when both are heterozygous and create the double dilution 'cream pearl'. Genetics Cream is an incomplete dominant dilution. That means its effect is different between heterozygous and homozygous state. When one copy of cream is present, it turns a red coat to a yellowish gold. Long red hair, like the mane and tail, become white. Dark hairs however, whether short (coat) or long (mane, tail), are mainly unaffected and remain dark. But when a horse inherits two copies of the cream gene, the effect is instantaneous. Both black and red short hairs are turned a creamy white, and long dark hairs can range from nearly white to a light brown. This gives the following results: * Chestnut + CR/n = palomino * Bay + CR/n = buckskin * Black + CR/n = smoky black * Chestnut + CR/CR = cremello * Bay + CR/CR = perlino * Black + CR/CR = smoky cream Palomino Chestnut + 1x cream = palomino Under the influence of cream, a chestnut coat colour turns yellow or gold. The shade may range from a yellowish cream to a dark and dappled yellow chocolate. It's easy to mistake a light palomino for a gold champagne or dark cremello, while the dark varieties can be seen as chestnuts or even silver bays. The mane and tail turn nearly white, of a creamy shade. Especially in combination with a deep gold coat, it's easy to understand why this colour can be so very popular. Buckskin Bay + 1x cream = buckskin When a single copy of cream is combined with bay, the result is a buckskin horse. The red bay coat turns a yellow or gold, but the points (mane, tail, lower legs and ear tips) remain dark. If the horse is more brown instead of bay, the coat becomes much darker. The hairs range from yellow to nearly black, with the softer parts of the body (belly, nose, etcetera) being the lightest. This colour is also called brown buckskin or smoky buckskin, and can be easily mistaken for an average brown horse when the number of yellow hairs is only minimal. Smoky black Black + 1x cream = smoky black If a black horse also has inherited a single copy of the cream gene, its colour is called smoky black. In heterozygous state, cream hardly affects black hair, and so a smoky black horse can be impossible to identify in a herd of otherwise black horses. Often, smoky black foals have lighter hairs in their ears, though this is no proof in itself. The light hairs usually disappear as the foal ages. Adult smoky black horses may appear lighter than average black horses, with red or brown hairs in their coat. Again, this is no evidence, as many 'normal' black horses can have a sunbleached coat which has a similar effect. Cremello Chestnut + 2x cream = cremello A cremello is a so-called 'double dilute'. It has a chestnut based coat, combined with two copies of the cream gene. Now, in its homozygous state, cream shows its full effect. Both the short and the long hairs become a creamy white, though ofter a little darker than true white horses. The skin becomes diluted as well. Normally grey, under the effort of two cream alleles, the skin becomes pinkish. This is especially visible around the eyes, nose and underneath the tail. The eyes change as well, becoming a light blue, a little lighter than the blue eyes of horses with white markings around them. Perlino Bay + 2x cream = perlino A perlino is similar to a cremello in that it has a light, creamy coat as well. This is caused by the two cream alleles on a bay based coat. Often though, the mane and tail are a little darker than the body, with a more reddish tint to them. Though there are perlinos with such light long hairs they are visually unrecognizable. As with cremello, the skin of a perlino becomes pink too, and the eyes are a light blue. Smoky cream Black + 2x cream = smoky cream A black horse with two cream alleles is called a smoky cream. The two copies of the cream gene lighten the black coat to a creamy white, though this can be darker than seen in cremellos or perlinos. Especially foals can appear much darker, though they lighten a little more as they age. The long hairs become a creamy white too, but like perlino, they often remain just a few shades darker than the body. Again, it is no evidence, and a DNA test voor base colour is required to ascertain the horse's true base colour underneath. A smoky cream also has pink skin and light blue eyes. Pearl We will discuss pearl more on its own page, though for now it is important to understand pearl is most likely found on the same locus as cream. That means a horse can be homozygous for cream and pearl, but not homozygous for both at the same time. They can, however, be heterozygous for both, and pass on one of the two copies to each foal. Pearl is likely to be very old. It appears in Iberian breeds such as the Pura Raza Española and lusitano, but also in gypsy horses, quarter horses, paints and peruvian pasos. Where cream is incomplete dominant, pearl is recessive, though it also combines with cream in heterozygous state to form the cream pearl double dilutes. As they are likely found on the same gene, the genetic possibilities are as follows: * Cn/Cn = no cream or pearl * CCR/Cn = single dilution of cream * CCR/CCR = double dilution of cream * Cprl/Cn = single dilution of pearl, no obvious effect * Cprl/Cprl = double pearl dilution * CCR/Cprl = double dilution with both cream and pearl Category:Colour Genetics